London: British palaeontologists have discovered a rare 200 million-year-old Ichthyosaur specimen from a private collection 22 years after it was originally found. Ichthyosaurs were a type of sea-going reptile that lived during the time of the dinosaurs.

The new fossil belongs to a rare species of "sea reptile" known as Wahlisaurus massarae and is the second known specimen of the entire species.

In 2016, Dean Lomax palaeontologist at the University of Manchester had discovered Wahlisaurus massarae from the collections of New Walk Museum and Art Gallery at Leicester.

He spotted several unusual features of the bones and determined that the features were unique.

But some palaeontologists questioned this and said it was just 'variation' of an existing species, Lomax noted.

Thus, collaborating with fossil collector Simon Carpenter, of Somerset, Lomax re-discovered a specimen of Wahlisaurus, originally collected in 1996 from a quarry in northern Somerset.

The specimen had an almost complete coracoid bone (part of the pectoral girdle) that has exactly the same unique features of the same bone in Wahlisaurus.

The new discovery, published in the journal Geological Journal, is from a time known as the Triassic-Jurassic boundary, right after a worldwide mass extinction.

For these reasons, the team have been unable to determine exactly whether the Ichthyosaur was latest Triassic or earliest Jurassic in age, although it is roughly 200 million-year-old.

"When you have just one specimen, 'variation' can be called upon, but when you double the number of specimens you have it gives even more credibility to your research," Lomax said.